Bacon said U.S. forces are not at a higher state of alert because of the testing. The threat of an arms race endangers the people of India and Pakistan, but does not directly threaten U.S. forces or U.S. interests, he said.

The testing by both countries, however, indirectly threatens U.S. interests, Bacon said. The United States wants to stop the proliferation of nuclear weapons, and it sees a South Asian arms race as destabilizing, he said.

India and Pakistan have short-range missiles that could carry nuclear warheads, but both are working on longer-range ballistic missiles. India's two types of short-range missiles can fly 150 and 250 kilometers, respectively. Bacon said India is developing another missile with a "more threatening" range of 2,000 kilometers.

Pakistan currently fields a missile with a 300-kilometer range and is working on one with a 1,000-kilometer range.

Bacon said tensions between the countries have escalated since India exploded its devices. Indian and Pakistani forces recently skirmished in Kashmir -- a border province both countries claim. Neither country has mobilized its armed forces.

President Clinton has imposed sanctions against both countries. Even before the tests, U.S. military contact with Pakistan has been extremely limited. The United States has no International Military Education and Training program or any foreign military sales with Pakistan.

Bacon said the United States was disappointed with Pakistan's decision to test. "We felt that this was an opportunity for Pakistan to show moderation and not escalation," Bacon said.

But this does not mean the U.S. counterproliferation policy is a failure. Bacon said there have been many counterproliferation successes around the world. "South Africa has renounced its [nuclear weapons] program," he said. The United States helped denuclearize the Ukraine, Belarus and Kazakhstan. The framework agreement in North Korea has been successful so far in stopping North Korea's nuclear program, Bacon said.

"The challenge the world faces is how to stop this situation from getting worse," Bacon said, calling the tests a clear setback. "How do you take a potentially risky situation and try to control it in a way that will improve security in a region rather than make the security situation less stable? That's the challenge."